I Need Help With My Relationship ( Need Girls Perspective )?

Ok i know this is gunna sound EXTREMELY corny but i am undoubtably in love with my girlfriend and i would like to be with her for a long time ( i mean marriage ) i just got out of high school (thats why it seems so corny many of you will think "high school sweethearts" its not its honestly much more than that) my problem is this her past 4-5 boyfriends were total assholes the kind that honestly only wanted a gf to make out or have sex with them etc and im complete opposite of that i love just talking to her making her laugh being there for her when shes mad sad anything i just like to be with her and shes not use to that at first she thought i was doing all that just for sex and i explained that im not that im into her for personality etc. so now shes a little better now problem is she said its hard and weird for her to open up and when she gets mad she just closes off society and stays by herself i used to do that and i know how much that sucks so i keep pushing for her to open up to me i need help and want all the girls to tell me if i should just wait and let her decide when to open up? the only problem is when she gets mad for dumb reasons i could make it better by just telling her she doesnt have to worry or help resolve the problem. Please i would not like negative criticism like oh your too young just leave her i would like some help i dont see myself with anybody else and i wanna resolve this but she doesnt like opening up. thanks ahead of time for any help :)